如果我导入“C”，则无法交叉编译

Question

Environment

• Windows 10
• Go 1.13.7

GOOS=windows
GOARCH=amd64
CGO_ENABLED=1

The problem

After days of trying to cross-compile my project, I figured that if one of my files does import "C", it seems that go build just skip it.

Here is my first file first.go :

package main

import "C"

type myFirstType struct {
    str string
}

func main() {
    v := myFirstType{str: "Hello"}
    printFirstTypeWithParam(v)
}

And here is the second second.go :

package main

import (
    "fmt"
)

func printFirstTypeWithParam(v myFirstType) {
    fmt.Println(v.str)
}

When I run go build , all is correct. But when I run env GOOS=linux go build , here is the output:

# test-package
.\second.go:7:32: undefined: myFirstType

As soon as I remove the import "C" line, all work perfectly.

Why is this a problem ?

In the real project, I use gopkg.in/goracle.v2 , and this library does use C libraries in drv.go :

/*
#cgo CFLAGS: -I./odpi/include -I./odpi/src -I./odpi/embed

#include <stdlib.h>

#include "dpi.c"
*/
import "C"

When I run the same build command on my project ( env GOOS=linux go build ), here is the output:

# myproject/vendor/gopkg.in/goracle.v2
vendor\gopkg.in\goracle.v2\drv_10.go:22:2: undefined: ConnectionParams
vendor\gopkg.in\goracle.v2\drv_10.go:23:2: undefined: drv

Both undefined type and variable are defined in this drv.go file.

Is this normal behavior, or am I missing something ?

Answer 1

goracle was moved to godror and doesn't support cross-compile. Read the same issue here: https://github.com/go-goracle/goracle/issues/171